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E Winkelmann

Publications and source records attributed to E Winkelmann.

At least 73 records · Page 4Linked to original sources
PubMed1981

The dorsal lateral geniculate nucleus of Tupaia glis: a Golgi, Nissl and acetylcholinesterase study.

Morphology of neurons and afferent axons in the dorsal lateral geniculate nucleus (dLGN) of the tree shrew (Tupaia glis) was studied using Golgi-Kopsch impregnated and Nissl stained material. Staining of acetylcholinesterase (AChE) could inform about the distribution of this enzyme in the tree shrew's dLGN. The results can be summarized as follows: 1. Two classes of neurons can be identified: class-I-neurons and class-II-neurons. Class-I-neurons correspond to geniculo-cortical relay neurons (GCR-neurons) and class-II-neurons correspond to local interneurons (I-neurons). 2. Class-I-neurons differ in their morphology depending on their laminar position. Tufted neurons with clusters of grape-like appendages in their branching zones resembling X-cells in the cat's dLGN are localized in the external laminae 5 and 4. In the superficial lamina 6 the dendrite domains of GCR-neurons are flattened and elongated. Dendrites seem not to penetrate laminar borders. The cells in layer 3 have the smallest soma and radiate dendrites. There is some evidence that GCR-neurons in this lamina represent W-cells (Carey et al., 1979). GCR-neurons in laminae 2 and 1 (innermost laminae) have the biggest somata. Their dendritic branching patterns make it difficult to classify the cells into tufted or radiate. Branching zones are rather smooth. These cells seem to be good candidates for Y-cells. 3. I-neurons could be identified in all laminae. Their dendrites preferentially take a dorso-ventral course. Only axon initial segments of these neurons were visible in Golgi preparations. 4. GCR-neurons and I-neurons could also be identified in Nissl preparations. The ratio GCR-neurons: I-neurons is about 10:1, i.e. 10% of all neurons are I-neurons. 5. In Golgi preparations some types of axons were impregnated. Type-1-axons resemble cortical afferents of other mammalian species. Type-2-axons (2a, 2b, 2c) do not leave single laminae in our material. Considering branching characteristics of their terminal zones, this finding could be a reference for their retinal origin. 6. Laminae 5, 4, 2, and 1 have a remarkable higher content of AChe than the laminae 6 and 3. The low level of ACHE in lamina 3 of the tree shrew's dLGN corresponds to the less activity of ACHE in the laminae 4 and 5 of Galago senegalensis (Fitzpatrick and Diamond, 1979), which like lamina 3 in Tupaia's dLGN project to layer I of the visual cortex (Carey et al., 1979).

Acetylcholinesterase↗
PubMed1980

[Ultrastrastructural and histochemical examinations of afferent pathways of the geniculate-cortical relay cells].

On the basis of ultrastructural and ultrahistochemical studies in the dorsal part of lateral geniculate nucleus (d LGN) of albino rat a topistical model of geniculo-cortical relay cell (GCR-cell) afferentiation is proposed. Retinal afferent terminals of type 2a and 2b and their synaptic properties are discussed in connection with slow and fast conducting retinofugal channels. Interneuronal contacts are represented by presynaptic dendritic specializations (P-bouton) and by axonal terminals (F-bouton) (LIEBERMAN and WEBSTER, 1974). These findings suggest that the function of interneurons may be dualistic. Cortical afferents are represented by small terminals with round agranular vesicles. Using the "false" transmitter 5-OH-DA we succeeded in demonstrating degenerating terminals with dense core vesicles. There is evidence that noradrenergic axons originating in the Locus coeruleus may contact with the distal dendritic parts of GCR-neurons.

Acetylcholinesterase↗
PubMed1979

Chemotherapeutically active anthraquinones. I. Aminoanthraquinones.

Basically substituted 2,6-diacetaminoanthraquinones proved to have an interesting in vivo effect against Entameba histolytica, but this effect was markedly exceeded by that of the series of the 2,6-diamidinoanthraquinones. A number of compounds of this series revealed a significantly stronger extraintestinal effect in the golden hamster than the standard amebicides metronidazole and tinidazole, but they were not superior to these compounds in their trichomonacidal effect, which was in general only a moderate one. In both substance classes, the amebicidal effect was confined to 2,6-disubstitution. Variations of the anthraquinone system resulted in a loss of activity. The structure-activity relationships are discussed.

Amebicides↗
PubMed1979

[Variability of the relay neurons in the corpus geniculatum laterale, pars dorsalis in the albino rat].

38 Golgi-impregnated relay cells from the Wistar rat's dLGN were investigated considering their possible differentiation into 2 types using camera lucida drawings with a magnification of 800. The following criteria were taken into account: 1. size of neurons (perikarya, size of dendritic domains) 2. structure of dendrites (number of dendrites, branching points, distribution of dendritic density in relation to the perikaryon, surface structures of dendrites). It was tried to correlate the investigated parameters quantitatively and qualitatively. The results showed that inspite of a missing clear subdivision into 2 types there exists a trend towards developing a second type of relay cells.

Animals↗
PubMed1979

[Fluorescence histochemical identification of axons using the GOLGI method].

Using fluorescence histochemical and GOLGI-methods afferent fibers in the albino rat's dorsal lateral geniculate nucleus (d LGN) have been investigated. We considered the following parameters: diameters of the axons, diameters of boutons, number of the boutons by 100 micrometers axon length. From comparison of the data from histochemical material with the data of the GOLGI-material follows that the noradrenergic terminals are identical with the type-4- and 5-axons. The terminal branching and synaptic contacts of the type-4- and 5-axons are discussed in connection with the aminergic innervation of this nucleus.

Afferent Pathways↗
PubMed1979

[Electron microscopic investigations on the neuroglia in a case of postnatal hypoxia (author's transl)].

The authors report a case of a six week-old infant, who has died from postnatal brian hypoxia. The ultrastructural investigation of the neuroglia shows lipid accumulations in most of astroglia cells, but only in a few oligodendrocytes. There is no correlation between glial metamorphosis and myelinization. Furthermore, there were found an immature neuropil, disturbed myelinization, and myelin and neuropil resorption processes. The study demonstrates the important role of hypoxic glial lesions n the evolution of the brain.

Astrocytes↗
PubMed1979

[Identification of nerve cells in the visual cortex of the rat using Nissl and Golgi-Kopsch methods].

The neurons of the visual cortex of the albino rat were studied using both the Nissl- and Golgi-Kopsch methods. In Nissl preparations we can distinguish between a group of neurons rich in cytoplasm, a group of neurons poor in cytoplasm and an intermediate group. In the Golgi preparations the neurons can be subdivided according to the shape of their cell bodies, dendrites and axons. Spiny cells with long axonal main trunks are pyramidal cells, multiangular cells and stellate cells of layer IV. Cells with spineless dendrites and short axonal arborization are basket cells, neuroglioform cells and small double bouquet cells. Due to its spines and the short axonal arborization, the coarse fusiform cell (Martinotti cell) is an intermediate type. We assume cells having long axons and dendritic spines are category I neurons and cells having short axons and no or a few spines are category II neurons (according to SZENTAGOTHAI 1973). On the basis of homological criterions and taxonomically relevant features references for identifying the cell group rich in cytoplasm and category I neurons, on the one hand, and the cell group poor in cytoplasm and category II neurons, on the other hand, were found. The group of cells rich in cytoplasm is related to pyramidal cells, multiangular cells and stellate cells of lamina IV. The group of cells poor in cytoplasm is discussed as corresponding to cells of lamina I, round or oval forms as basket cells and neuroglioform cells, fusiform cells as double bouquet cells. The intermediate cell form in the Nissl preparations is according to the Martinotti cell in Golgi material. These findings allow quantitative studies about particular cell populations and can, completed with electron microscopical date, instruct computer models to simulate the complicate neuronal network of the visual cortex.

Animals↗
PubMed1978

[The catecholaminergic connections of the visual system of the albino rat (author's transl)].

By using the glyoxylic acid method of DE LA Torre and Surgeon (1976), occurrence, distribution and origin of catecholamines were investigated in the visual system of the albino rat. A dense network of green fluorescent terminals and preterminals could be detected in the dLGN. The spreading of terminals of catecholaminergic fibres had been observed in laminae I and II of the visual cortex. Investigation of lamina I with the Golgi-Kopsch method showed axons the thickness of which was below 1 micron, and with varicosities with a distance of approximately 3.5 micron, having a diameter of 2 to 4 micron. These axons might be identical with the fluorescent-histochemically represented terminals. Taking into account the course of catecholaminergic axons it can be concluded that the pyramidal cells of the neocortex, the spiny dendrites of which are heavily branched in the lamina I, are affected. After application of horseradish-peroxidase in the dLGN labelled cells have been found in the locus coeruleus (A6) only. After application of the enzyme in the visual cortex, labelled cells have been observed in the nuclei A 6 and A2. The pathway of catecholaminergic axons from the nucleus of origin to the terminal regions was investigated using the "false transmitter" 6-OH-DA. The results can be seen in a diagram.

Animals↗
PubMed1978

Chemotherapeutically acitve nitro compounds. 4. 5-Nitroimidazoles (Part III).

More than 100 1-methyl-5-nitroimidazoles substituted in the 2-position via an oxymethyl group were synthesized and their structure-activity relationship toward various protozoa was investigated. Among the derivatives substituted with an aromatic radical there are most of the compounds which are highly effective against trichomonads; 9 preparations are superior to tinidazole and 29 are superior to metronidazole in mice infected with Trichomonas fetus, and 9 compounds exhibit a better effect than metronidazole in golden hamsters intrahepatically infected with Entamoeba histolytica. In the same series one dialkylamino-acetamide derivative shows excellent trypanocidal activity in the NMRI mouse, but this effect is limited to Trypanosoma brucei; 12 preparations developed a trypanocidal effect only after relatively high doses; their range of efficacy included Trypanosoma cruzi, among others, after repeated treatment. Of the carboxyl acid, carbamic acid and sulphonic acid esters synthesized only the already known group of carbamic acid esters possesses a pronounced antiprotozoal effect. Among the preparations substituted with a heterocyclic radical some of the pyridine derivatives proved to have distinct trichomonacidal activity. The influence of the type of substitution and the stability of the C-X bond in 2-substituted 5-nitroimidazoles of all compounds synthesized so far (I--III, 4th report) are discussed in 2 tables.

Animals↗
PubMed1978

Chemotherapeutically active nitro compounds. 4.5-Nitroimidazoles (Part II).

More than 170 1-methyl-5-nitroimidazoles substituted in the 2-position via an aminomethyl, thiomethyl, sulphinylmethyl or sulphonylmethyl group were synthesized and tested for their effect against various protozoa. In the NMRI mouse which had been i.p. infected with Trichomonas fetus 2 compounds showed an effect superior to that of tinidazole and 31 showed similarly good efficacy as that compound. In comparison with metronidazole 54 preparations proved to be distinctly more active, while 34 others lay in the range of efficacy of the standard compound. A large majority of the most active derivatives is substituted in the 2-position via a C--S bridge with heterocyclics, particularly with a pyridyl radical. An effect against Entamoeba histolytica in the intrahepatically infected golden hamster was observed much less often. Only 14 preparations developed a systemic effect comparable with that of metronidazole. In the NMRI mouse infected i.p. with Trypanosoma brucei or s.c. with T. cruzi parasitemia was clearly influenced by 11 compounds. With a few exceptions a trypanocidal effect against T. brucei occurred only at high doses. Only 3 compounds showed pronounced suppressive activity against blood forms of T. cruzi and only after prolonged treatment. The structure-activity relationship of the new 5-nitroimidazoles is discussed.

Animals↗
PubMed1978

Chemotherapeutically active nitro-derivatives. 4. 5-Nitroimidazoles (Part IV).

16 novel 1-methyl-5-nitroimidazoles substituted at 2-position were examined for activity against various protozoa, in particular trichomonads in NMRI mice and amebae in golden hamsters. Six of the compounds proved to be superior to metronidazole and one superior to tinidazole against trichomonads. The compounds exhibited no marked effect against amebae and trypanosomes. The structure-activity relationships of the new compounds are discussed.

Amebiasis↗
PubMed1978

Phylogenetical changes and functional specializations in the dorsal lateral geniculate nucleus (dLGN) of mammals.

Depending on their visual specialization and their place in the zoological system the mammalian species show some peculiarities in the morphology of the dorsal lateral geniculate nucleus (dLGN). The lamination of dLGN can be find in mammals with a highly developed visual system and a proportionally big part of ipsilaterally projecting retinogeniculate fibres. Number and sequence of ipsi- and contralaterally innervated laminae varies between species of different taxonomical categories. Hence these features depend on phylogenetical trends which could traced back to the beginning of the "mammalian radiation" in the cretaceous period and the earliest tertiary. Ancestral conditions may be found in mammals with an unlaminated dLGN and a medially located ipsilaterally innervated part. It may be registrated that a cytoarchitectonical separation of laminae (concerning the ipsi- and contralateral innervation) is the secondary step after fibre anatomical separation. The most primitive status may be realized in mammals having a zone of mixed ipsi- and contralateral fibre input. Some conclusions are made with regard to the suitability of lab mammals for generalization of results in the dLGN morphology.

Animals↗
PubMed1978

[Axon-like glial extensions in the pars ventralis of the corpus geniculatum laterale (CGLv) of the albino rat].

In sections of the Corpus geniculatum laterale, pars ventralis (CGLv) of adult albino rats impregnated according to Golgi-Kopsch, structures are visible very similar to long unbranched axons with large boutons en passage. Within the CGLv these axon-like structures can be followed parallel to the optic tract. Generally they take a ventro-dorsal, exceptionally a dorso-ventral course. As well in Golgi-Kopsch material as in sections in which glial cells are specifically impregnated the described structures could be traced to cells mainly located subpial in the Tractus opticus. Within the optic tract these axon-like structures change their appearance looking similar as the numerous other processes originating from these cells too. These other processes take a course right-angled to the optic fibers and in general they don't bear axon-like structures as described. In our opinion based also on investigations of Nissl-stained sections the origination cells represent a specialized type of astroglia of until now unknown function.

Afferent Pathways↗
PubMed1977

1,4-Bis-[1-methyl-5-nitroimidazolyl-(2-methyleneimino)]-piperazine, a new drug with marked activity against Entamoeba histolytica. Short communication.

1,4-Bis-[1-methyl-5-nitroimidazolyl-(2-methyleneimino)]-piperazine (HOE 316) administered orally produces an effect which is clearly superior to that of metronidazole against Entamoeba histolytica in the golden hamster and slightly inferior against Trichomonas fetus and T. vaginalis in the mouse. The acute tolerance of the compound is very good (LD 50% greater than 10 g/kg body weight). It is assumed that the possible main metabolite of HOE 316 is a monohydrazone: 1-methyl-2-(4-amino-piperazino-1-imino-methyl)-5-nitroimidazole.

Animals↗
PubMed1977

Chemotherapeutically active nitro compounds. 4. 5-Nitroimidazoles (Part I).

More than 135 new 2-methyl-5-nitroimidazoles substituted in 1-position and 1-methyl-5-nitroimidazoles substituted in 2-position were investigated for their activity against various protozoan species, in particular Entamoeba histolytica in the golden hamster, Trichomonas fetus, Trypanosoma brucei and T. cruzi in the NMRI mouse. Among the nitroimidazoles substituted in the 1-position only two preparations exhibited a similar effect as metronidazole preparations exhibited a similar effect as metronidazole against T. fetus. In the class of the nitroimidazoles substituted in the 2-position 16 compounds were as effective as metronidazole, 19 showed an effect superior to metronidazole, 1 was as good as tinidazole and 2 exhibited an activity superior to tinidazole against T. fetus. Only few compounds displayed any amoebicidal activity. Of the mono and bis-hydrazones of 1-methyl-5-nitroimidazole-2-aldehyde substituted in the 2-position 3 compounds had an amoebicidal effect 2 to 8 times stronger than that of metronidazole. Only few representatives of the 1-methyl-5-nitroimidazoles substituted in the 2-position produced a useful trypanocidal effect when given in relatively high doses. The structure-activity relationship of 5-nitroimidazole derivatives has been discussed.

Animals↗